Bernie Badger: Herschel can keep cool only a little longer

11:38 PM,
Mar. 21, 2013

This artist's impression of Herschel is set against an image captured by the observatory, showing baby stars forming in the Rosette nebula. The bright spots are dusty cocoons containing massive forming stars, each one up to ten times the mass of our own sun.

Written by

Bernie Badger
Satellites and Planets

Another of the world's great space telescopes is reaching the end of its useful life. The 3.5 meter diameter Herschel Telescope had the largest mirror yet put into space. It has probed the far infrared and sub-millimeter wavelengths to detect some of the coolest objects out there.

To do this, it needs to cool off its instruments to just a few degrees above absolute zero (0 on the Kelvin scale). As liquid helium boils, it maintains a temperature of 1.65 K.

Like a marathon runner keeping cool by splashing water on himself, the Herschel telescope has a supply of liquid helium that it evaporates to ...